< BK21+ BEST Seminar Series Announcement> 

Time and Date : 16:00 ~ 17:00 Monday 11/18/2019

Place : B041, Engineering Building #2

Title : Applications of Single-Molecule Techniques: Characterization of Supramolecular Machinery in Microorganism and Visualization of Biomolecule in Virus Removal Filter
Abstract:
Motor proteins are molecular machines that convert chemical energy into mechanical work. In addition to existing studies performed on the linear motors found in eukaryotic cells, researchers in biophysics have also focused on rotary motors such as bacterial flagellar motor (BFM) and ATP synthase, both of which localize at cell membranes. The research group including Nishizaka contributed to correlate all chemical states to specific mechanical events in motors by visualizing single chemical reactions under the advanced optical microscope. From the structural point of view, conformational changes of  catalytic subunit in the soluble subcomplex of ATP synthase, F1-ATPase, was directly visualized at the single molecular level. Additionally, behaviors of the shaft were also addressed through a series of microscopy techniques. Recent studies showed that there exists another ATP-driven protein motor in life: the rotary machinery that rotates archaeal flagella (archaella). None of the archaellar motility structure is homologous to any BMF proteins. Rotation speed, stepwise movement, and variable directionality of the motor of Halobacterium salinarum were described in previous studies. We further presented recent experimental work discerning the molecular mechanism underlying how the archaellar motor protein FlaI drives rotation by generation of motor torque.
  In the latter half of the talk, the new application of the confocal microscope system will be presented: the visualization of biomolecules in artificial matrix comprised of polymer macromolecule. In the medical industry, filters to remove viruses from biotherapeutic products have been developed and are used to ensure their safety for decades. However, the mechanisms of how viruses are trapped in the intricate structure of the filter membrane have not been studied in detail. Our group developed a new experimental setup to examine biomolecules directly under an optical microscope, and demonstrated the accumulation of fluorescent virus-like-particle at a retention layer of the membrane.

Presenter: Prof. Takayuki Nishizaka / Department of Physics, Gakushuin University

Host: Prof. Kim, Donghyun, Yonsei EEE